Magnetically responsive fluid switch

ABSTRACT

A switch comprises two electrically conducting magnetic tubes with their longitudinal axes in alignment wherein each tube has an electrically conducting magnetic wire coaxially located within it. The adjacent ends of both the wires and tubes are spaced apart and coated with a magnetically responsive mercury. When the adjacent ends of the tubes and the wires are controlled to be of opposite magnetic polarities, the mercury of these ends coalesces, producing a conductive path between the tubes and between the wires. Alternatively, when the adjacent ends of the tubes and wires are controlled to be of the same magnetic polarity, the mercury separates due to magnetic repulsion and the conductive path is broken.

Remec Nov. 6, 1973 MAGNETICALLY RESPONSIVE FLUID SWITCH Inventor: Matthew Joseph Remec, North Riverside, Ill. 60546 Bell Telephone Laboratories, Incoporated, Murray Hill, NJ.

Filed: Nov. 24, 1972 Appl. No.: 309,243

Assignee:

US. Cl. 335/51, 200/214, 333/97 S, 335/47 Int. Cl. II0lh 1/08 Fieldof Search 335/47 X, 48, 49, 335/50, 51 X, 52, 53, 54, 55, 56, 57, 58, 4; 333/975 X, 7 R; 200/214 X I-Iurvitz 335/47 3,643,185 2/1972 Zimmer 335/58 Primary ExaminerHarold Broome Att0rney-W. L. Keefauver ABSTRACT A switch comprises two electrically conducting magnetic tubes with their longitudinal axes in alignment wherein each tube has an electrically conducting magnetic wire coaxially located within it. The adjacent ends of both the wires and tubes are spaced apart and coated with a magnetically responsive mercury. When the adjacent ends of the tubes and the wires are controlled to be of opposite magnetic polarities, the mercury of these ends coalesces, producing a conductive path between the tubes and between the wires. Alternatively, when the adjacent ends of the tubes and wires are controlled to be of the same magnetic polarity, the mercury separates due to magnetic repulsion and the conductive path is broken.

6 Claims, 1 Drawing Figure MAGNETICALLY RESPONSIVE FLUID SWITCH BACKGROUND OF THE INVENTIOi l The present invention relates to switches for coaxial transmission lines and more particularly to switches which connect and disconnect both inner and outer coaxial conductors. I

Coaxial lines are generally used to carry high ''frequency electrical signals. When high frequency electrical signals are transmitted by a coaxial line, the outer conductor must completely surround the inner conductor through the entire length of the coaxial line or the signals will radiate from it. Also an impedance discontinuity along such a line carrying high frequency signals will cause undesirable reflections of the transmitted signal.

Most prior art arrangements for switching two conductors comprise simply a separate switch to provide mechanical and electrical continuity for each of the conductors. When this prior art arrangement is employed to switch both conductors of a coaxial transmission line, the two conductors of that coaxial line must be separated to be connected to the switch elements. Since such switch elements provide only mechanical and electrical continuity and not the complete physical continuity required for shielding, the shielding of one conductor by the other is lost at the point of switching. Further, the separation of the conductors creates an impedance discontinuity which can cause undesirable reflections.

To avoid these problems of loss of shielding. and impedance discontinuity, coaxial switches of the prior art generally comprise a nonswitchable outer conductor completely surrounding a switch connected in series with the inner conductor. Although radiationfrom the prior art coaxial switches is controlled, since'the inner conductor is completely surrounded, these switches cannot be used to switch the outer conductor. Further, the switch for the inner conductor generally employs metallic contacts. The use of metallic'contactsrequires 'sive' construction techniques to avoid signal Jrefle'ctions due to impedance discontinuity and do not permit switching both the outer and innerconductorsofacoaxial conductor.

SUMMARY OF THE INVENTION The present invention is a noncomplex switch for ling the adjacent ends of the tubes and wires to be of the same polarity causes the fluid to separate, resulting in an open circuit between the tubes and an open circuit between the wires. Since the conductive magnetically responsive fluid coats the entire adjacent ends of both tubes, the outer conductor completely shields the inner conductor when the switch is closed. Further, due to the-small separation possible between like conductors, any impedance discontinuity is kept to a minimum. The invention thus makes it possible to switch both conductors of a coaxial line with no significant sacrifice of the qualities otherwise inherent in the line.

DETAILED DESCRIPTION The present invention will be more readily understood when read with respect to the sole figure of the drawing, which is a longitudinal cross section of one specific embodiment.

The figure is a cross sectional view of an embodiment of the present invention in the open circuit state. The switch shown is a coaxial switch including two cylindrical ferromagnetic outer conductors 1 and 2, each of which has a hollow cylindrical passage through it. A ferromagnetic inner conductor 3 is retained within and substantially along the axis of the passage through outer conductor 1 by a dielectric support 4. In the present embodiment, this dielectric support 4 is comprised of glass which provides an airtight seal across the passage through outer conductor 1. An end 5 of inner conductor 3 terminates substantially at the plane formed by an end 6 of outer conductor 1.

The hollow passage through outer conductor 2 contains a ferromagnetic inner conductor 7 which is retained substantially along the axis of that passage by a dielectric support 8. Dielectric support 8 in this embodiment ismade of glass and provides an airtight seal acrossthe passage through the outer conductor 2. An end 9 of inner conductor 3 terminates substantially at the plane formed by an end 10 of outer conductor 2.

The two outer conductors l and 2 are retained by a rigid insulator 11, which coats the outer surface of the conductors 1 and 2, such that their longitudinal axes are substantially colinear and the adjacent ends 6 and 10 of outer conductors l and 2, respectively, are spaced apart. Since the inner conductor ends 5 and 9 terminate at substantially the plane of the outer conductor ends 6 and 10, respectively, the adjacent ends switchingboth the-outer and inner'condujctors of *a-co-' 1 axial line while maintaining complete shielding :byth'e outerconductor. and causing a minimum of impedance discontinuity.

in accordance with the present invention, the adjacent ends of a pair of spaced-apart electrically'conduct ing tubes and the adjacent ends of a pair of"-spacedapart electrically conducting wires, one of which is'located within each of the tubes, are coated with acouductive magnetically responsive fluid. Controllingthe magnetic polarity of the adjacent ends of the tubesand the adjacent ends of the-wires to be of opposite-magneticpolarities causes the fluidcoatingsimilar conductors to coalesce, creating a conductive pathbet-ween the tubes and between the wires. Alternatively, control- 5'and9 of the inner conductors are also spaced apart. The adjacent annular ends 6 and 10 of conductors l and '2, respectively, are coated with a conductive magnetically responsive fluid 12. The adjacent ends 5 and 9ofinner conductors 3 and 7, respectively, are also .7. These coils are used to control the switch. A potential is applied between terminals 15 and 16 of coil 14 to create'a magnetic field. The ferromagnetic conductors l and 3 respond to this magnetic field and become magnetically polarized. ln the present example the potential applied to terminals 15 and 16 produces a magnetic field which induces end 6 of conductor 1 and end of conductor 3 to be north magnetic poles. The polarity of the potential applied between terminals 15 and 16 remains constant during the switching operation, causing ends 5 and 6 of conductors 3 and 1, respectively, to remain north magnetic poles.

Ends 9 and of conductors 7 and 2, respectively, are controlled to be either north or south magnetic poles by controlling the polarity of the potential applied to terminals 18 and 19 of coil 17. When the conductor ends 9 and 10 are controlled to be north mag netic poles, the conductive magnetically responsive fluid coating these ends 9 and 10 will repel the conductive magnetically responsive fluid coating the conductor ends 5 and 6 which are also north magnetic poles. This repulsion creates an open circuit between the outer conductors l and 2 and between the inner conductors 3 and 7. Alternatively, when the conductor ends 9 and 10 are controlled to be south magnetic poles, the conductive magnetically responsive fluid coating these ends will attract the conductive magnetically responsive fluid coating the conductor ends 5 and 6 which are north magnetic poles. In response to this attraction, the conductive magnetically responsive fluid coating the ends 6 and 10 of the conductors l and 2, respectively, will coalesce around the entire annular surface formed by these ends, resulting in a conductive path between conductors 1 and 2 around their entire circumference. Also in response to the attraction, the conductive magnetically responsive fluid coating the conductor ends 5 and 9 will coalesce, resulting in a conductive path between the inner conductors 3 and 7.

Also in accordance with the present invention, the switch of this embodiment may be a latching switch. When the switch is to be a latching switch, the outer conductor 2 and the inner conductor 7 are bistable magnetic members of a material which exhibits mag netic retentivity but which may be switched by the application of a suitable magnetic field to one or the other of the two magnetic polarities. The so-called square looped materials of which ferrites are a class possess these characteristics. The remainder of the latching switch is identical to the switch previously described with respect to the figure.

In the following example of the operation of the latching switch it is assumed that the ends 5 and 6 of the conductors 3 and 1, respectively, are controlled to be north magnetic poles. To place the switch in the open state,,a potential pulse is applied between terminals 18 and 19 of coil 17 which causes the bistable magnetic conductors 2 and 7 to have north magnetic poles at their ends 10 and 9, respectively. Due to the properties of the bistable magnetic material, the ends 9 and 10 remain north magnetic poles after the potential pulse terminates. As previously described, when the adjacent ends of the conductors are of the same magnetic polarity, the conductive magnetically responsive fluid separates, resulting in an open circuit.

Alternatively, when a potential pulse is applied to terminals 18 and 19 of coil 17, causing the bistable magnetic conductors 2 and 7 to have a south magnetic pole at their ends 10 and 9, respectively, the conductive magnetically responsive fluid coalesces, as previously described, completing a circuit between the conductors 1 and 2 and between th conductors 3 and 7. Since the bistable magnetic conductors 2 and7 retain their magnetic polarity after the pulse applied to coil 17 terminates, the switch remains in the closed state until the magnetic polarity of conductors 2 and 7 is changed by another pulse.

What is claimed is:

1. An electrical switch comprising:

a pair of magnetically responsive outer conductors I each having a hollow passage therethrough;

a pair of magnetically responsive inner conductors each within a respective one of said outer conductors;

conductive magnetically responsive fluid coating one end of each of said outer conductors and one end of each of said inner conductors; and

means for retaining said outer conductors and said inner conductors so that said conductive magnetically responsive fluid coating said conductor ends coalesces between said inner conductors and between said outer conductors in response to the magnetic polarization of said conductors in a predetermined direction.

2. An electrical switch in accordance with the claim 1 wherein a selected one of said outer conductors and the inner conductor within said selected tube are of a material which exhibits magnetic retentivity.

3. An electrical switch in accordance with the claim 1 further including a means for controlling the magnetic polarity of said outer and said inner conductors.

4. A latching electrical switch comprising:

a first magnetically responsive outer conductor having a hollow passage therethrough in which a first magntically responsive inner conductor is coaxially retained;

a second outer conductor having a hollow passage therethrough in which a second inner conductor is coaxially retained, wherein said second outer conductor and said second inner conductor are of a material which exhibits magnetic retentivity;

magnetically responsive mercury coating one end of each of said outer conductors and each of said inner conductors; and

means for retaining said outer conductors and said inner conductors so that said magnetically responsive mercury coating said conductor ends coalesces between said inner conductors and between said outer conductors in response to the magnetic polarization of said conductors in a predetermined direction.

5. A latching electrical switch in accordance with the claim 4 further comprising means for biasing said mercury coated ends of said first outer conductor and said first inner conductor to one magnetic polarity and;

control means for controlling said mercury coated ends of said second outer conductor and said second inner conductor to exhibit a selected magnetic polarity.

6. A latching electrical switch in accordance with the claim 5 wherein said control means comprises:

a coil around said second outer conductor and said second inner conductor; and

means for applying a potential pulse of either polarity tosaid coil.

* a: it 0- "UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3771O8O Dated November 973 Inventor(5) Matthew J. Reme c It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column L, line 26, "said selected tube" should read --sa.id selected outer conductor-.

Signed and sealed this 16th day of April 197b,.

(SEAL) At be 8 t EDWARD I'LFLETCHERJR. c, MARSHALL DANN Attesting Officer Commissioner of Patents uscoMM-oc come-pe i US. GOVIINMINT PRINTING OFIICI. 1 I." 0-3604.

FORM PO-105O (10-69) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,771,080 Dated November 6, 1973 Patent No.

n we ofl Matthew J. Reme c It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column line 26, "said selected tube" should read --sa.id selected outer Conductor".

Signed and sealed this 16th day of April 1971;.

(SEAL) Attest: EDWARD ILFLEIGHERJ C, MARSHALLDANN Attesting Officer Commissioner of Patents USCOMM-DC 603704 69 FORM PO-IOSO (10-69) us. aovummn mm'ms omen nu man-2:4 

1. An electrical switch comprising: a pair of magnetically responsive outer conductors each having a hollow passage therethrough; a pair of magnetically responsive inner conductors each within a respective one of said outer conductors; conductive magnetically responsive fluid coating one enD of each of said outer conductors and one end of each of said inner conductors; and means for retaining said outer conductors and said inner conductors so that said conductive magnetically responsive fluid coating said conductor ends coalesces between said inner conductors and between said outer conductors in response to the magnetic polarization of said conductors in a predetermined direction.
 2. An electrical switch in accordance with the claim 1 wherein a selected one of said outer conductors and the inner conductor within said selected tube are of a material which exhibits magnetic retentivity.
 3. An electrical switch in accordance with the claim 1 further including a means for controlling the magnetic polarity of said outer and said inner conductors.
 4. A latching electrical switch comprising: a first magnetically responsive outer conductor having a hollow passage therethrough in which a first magntically responsive inner conductor is coaxially retained; a second outer conductor having a hollow passage therethrough in which a second inner conductor is coaxially retained, wherein said second outer conductor and said second inner conductor are of a material which exhibits magnetic retentivity; magnetically responsive mercury coating one end of each of said outer conductors and each of said inner conductors; and means for retaining said outer conductors and said inner conductors so that said magnetically responsive mercury coating said conductor ends coalesces between said inner conductors and between said outer conductors in response to the magnetic polarization of said conductors in a predetermined direction.
 5. A latching electrical switch in accordance with the claim 4 further comprising means for biasing said mercury coated ends of said first outer conductor and said first inner conductor to one magnetic polarity and; control means for controlling said mercury coated ends of said second outer conductor and said second inner conductor to exhibit a selected magnetic polarity.
 6. A latching electrical switch in accordance with the claim 5 wherein said control means comprises: a coil around said second outer conductor and said second inner conductor; and means for applying a potential pulse of either polarity to said coil. 